1. Field of the Invention
The present invention relates to a device and a method for taking out a plurality of stacked sheets one by one while they are separated from one another.
2. Description of the Related Art
Conventionally, as a sheet takeout device of this type, there has been known a device which feeds a plurality of sheets in a stacked state, presses these sheets to a takeout roller in a piling up direction, and rotates the takeout roller to take out sheets brought into contact with the roller one by one to a conveying path. To prevent the taking-out of the stacked sheets, this device includes a feed roller rotated in a forward direction and a separation roller for applying a separation force of an opposite direction to sandwich the conveying path (e.g., see Jpn. Pat. Appln. KOKAI Publication No. 2003-341860).
The separation roller is associatively rotated in a conveying direction when one sheet is taken out to pass through a nip between the separation and feed rollers, and rotated in a direction reverse to the conveying direction when two sheets are taken out in a stacked state to pass through the nip. Accordingly, the sheets taken out in the stacked state can be separated from one another to be conveyed one by one.
However, in the device of this type, when a certain separation force is applied to all the sheets under the same conditions, various problems occur. For example, when a separation force in an opposite direction is applied while a conveying force is applied to thin and inflexible sheets in a forward direction, the sheets may be bent or cut. When a separation force is applied to a thin sealed letter made of vinyl, the letter may be destroyed because of interaction with the feed roller.